char * convertToTitle(int columnNumber){
    char *ans = (char *)malloc(sizeof(char)*10);
    ans[9] = '\0';
    int counter = 8;
    int temp = 26;
    while(columnNumber > 0) {
        ans[counter] = columnNumber % 26 + 'A' - 1;
        printf("col = %d, %d\n", columnNumber, columnNumber % 26);
        columnNumber /= 26;
        if(ans[counter] == '@') {
            ans[counter] = 'Z';
            columnNumber--;
        }
        counter--;
    }
    return ans + counter + 1;
}